Wyoming - Powder River Basin - Coal

State: Wyoming
Region: SE Montana, NE Wyoming
Description: The Powder River Basin is a geologic region in southeast Montana and northeast Wyoming, known for its coal deposits. It is both a topographic drainage and geologic structural basin. It is the single largest source of coal mined in the United States and the region supplies about 40 percent of coal in the United States.

 

The region is also a major producer of natural gas through a process called coal-bed methane extraction. Underground coal seams are dewatered through pumping, which reduces pressure and releases trapped gases up to the well head.

The United States Geological Survey (USGS) has conducted a series of studies on the economic accessibility of coal in the major coal producing regions of the country. The studies have typically found that only a small fraction of the coal will be economically accessible at current prices . Estimates are that only 6 percent of the original resource is currently economically recoverable.

The mines in the Powder River Basin typically have less than 20 years of life remaining. Almost all of the coal in the Powder River Basin is federally owned and further mine expansions will require a series of federal and state approvals.

Recent controversy surrounds the extensive coal bed methane extraction in the region. In the last decade, nearly 7,000 such wells have been drilled. An extensive network of gas pipelines connecting these wells has been built, along with a series of pressurization plants, as well as power lines to provide electricity to operate the system. In addition, thousands of miles of new access roads have been constructed.

Extracting the gas requires that water be pumped to the surface to release gas trapped in the coal seam. While some of the water is successfully utilized in agriculture production such as livestock water and crop irrigation, some waters are naturally high in salinity and sodium adsorption ratio. There has been controversy on how to best manage these saline waters.

The drive for coal, oil and coal bed methane is quickly transforming the region and threatens to permanently change the area for the farmers, ranchers, tribes and wildlife that call it home.